The Porsche 917/30 is the most powerful ever Porsche racing car. At full boost, the turbocharged flat 12 unleashed 1100, with flash readings of 1450 horsepower possible. The flat 16 powerplant was abandoned because of too little power, the test flat 16 produced 650 horsepower, while the first turbo flat 12 produced about 800+ horsepower.

Compared to the previous Can Am Porsches, the 917/30 had a wheelbase about 200 mm longer than before. This was an effort to tame the evil handling characteristics of the shorter 917/10. The wheelbase of the 917/10 was carried over from the 917 and the 908. The reason why the wheelbase was short at first was due to chassis rigidity. Porsche engineers knew that a longer wheelbase would require more metal tubings to stiffen the chassis back to previous levels, making the chassis heavier than before, robbing them the advantage of the extra horsepower the flat 12 gave. This very short wheelbase allied to enormous horsepower made the 917/10 very difficult to handle. The longer wheelbase of the 917/30 made the car much more predictable in terms of handling without sacrificing agility of the car.

The enlongated tail of the 917/30 was the idea of Mark Donohue. At Le Mans in 1970/71, the 917s sported longtails, also known as langhecks. The use of this enlongated tail was to increase top speed without sacrificing alot of downforce by reducing drag, although the early cars didn't exactly handle...The longtail boosted the 917/30's top speed from 360+km/h to about 380+km/h.